2005年 · 第118卷第16期

Abstract：Background Adrenomedullin (ADM), a potent hypotensive small peptide, was recently found to inhibit the proliferation of glomerular mesangial cells (MsC) in vitro and to attenuate glomerular lesions in vivo, however the mechanisms remain poorly understood. In this study, we attempted to elucidate them using molecular signal transduction. Methods Cultured rat MsC were treated with ADM and several inhibitors of signalling molecules. Methyl thiazoleterazolium (MTT) assay and BrdU incorporation method were employed for examining MsC proliferation. Western blot analysis was used for detecting total mitogen activated protein kinases (t-MAPKs) and phosphorylated MAPKs (p-MAPKs) proteins. Results ADM suppressed MsC proliferation in a concentration- and time-dependent fashion. This response was inhibited by ADM receptor antagonist CGRP8-37 and a potent protein kinase-A (PKA) inhibitor, H89. Forskolin, a direct adenylate cyclase activator, also significantly inhibited MsC proliferation. SB203580, a P38MAPK inhibitor, and U0126, a MEK inhibitor, both completely blocked ADM mediated responses in MsC. However, curcumin, a SAPK/JNK inhibitor, and GF109203X, a potent protein kinase-C (PKC) inhibitor, had no effect on MsC growth. Western blot analysis showed that ADM did not change the expression of t-MAPKs but increased p-SAPK/JNK and p-P38MAPK levels and decreased p-ERK level. These responses were inhibited by CGRP8-37. All these kinase phosphorylations, except for the increase in p-SAPK/JNK, could be stimulated using forskolin. In addition, only ADM mediated changes in ERK and P38MAPK phosphorylations were inhibited by H89. GF109203X did not affect ADM induced changes in three p-MAPKs expressions.Conclusions ADM inhibits MsC proliferation possibly through cAMP-PKA pathway. Both phosphorylations of ERK and P38MAPK pathways were necessary in mediating the antiproliferative response of ADM. It does not preclude the involvement of cAMP independent pathways in the ADM mediated responses。

Abstract：Background Miniature pig (minipig) is increasingly used as a large animal model for a variety of biomedical studies. Little information is available in the literature on anatomy, histology and sialograghy of the submandibular gland of the minipig. The purpose of this study was to characterize the morphology of a miniature pig's (minipig) submandibular gland as a large animal model for further biomedical studies.Methods Five minipigs were subjected to sialographic, anatomic, histologic, histochemical and ultrastructural evaluations for submandibular glands. Results Sialograms showed a long, horizontal main excretory duct and a pear-shaped gland located inferoposterior to the angle of the mandible. The submandibular glands lied superficial to the suprahyoid, and infrahyoid muscle groups, and were covered by the inferior portion of the parotid gland. The submandibular glands were characterized by a mixed parenchyma of mucous and serous secretory acini. Alcian blue (AB) staining and periodic acid-Schiff (PAS) reactions demon-strated that minipig submandibular glands synthesized and secreted acid mucous substances by serous cells and polysaccharide, and neutral mucous substances, by mucous cells. Conclusion The submandibular gland of the minipig is considered a useful large salivary gland animal model for biomedical studies.

Abstract：Background Peroxisome proliferator-activated receptor-gamma (PPARγ) is a kind of ligand-activated transcription factors binding to peroxisome proliferator response element (PPRE), a specific recognition site. It is thought to play a critical role in glucose and lipid metabolism and in inflammation control. The aim of this study was to establish a new cellular model for the quick screening of lipid-lowering drugs, which may be effective as PPAR-γ ligands on the PPRE-mediated pathway regulatory system. Methods Two plasmids were constructed: pXOE-PPARγ, in which the human PPARγ gene was in the downstream of TFⅢA gene promoter, and pLXRN-PPRE-d2EGFP, in which the enhanced green fluorescent protein (EGFP) gene was subcloned into PPRE. The xenopus oocytes were injected with these two plamids, and consequently treated with prostaglandin E1, pioglitazone, and different kinds of lipid-lowering drugs. After 3 days, the oocytes were observed under a fluorescence microscope. To confirm the drug action,we injected pXOE-PPARγ plasmid into the oocytes, which then treated with prostaglandin E1and Hawthorn flavonoids. The mass of expressed lipoprotein lipase (LPL) in the cells was determined by enzyme labeling linked immunosorbent assay (ELISA).Conclusions It is possible to establish a PPRE regulatory EGFP reporter system in xenopus oocytes to monitor the activity of PPARγ ligand. Hawthorn flavonoids can increase the expression of gene downsteam of PPRE by effect on the PPRE pathway regulatory system。

Abstract：Background Paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridinium), a widely used herbicide that is structurally similar to the known dopaminergic neurotoxicant MPTP (1-methyl-1,2,3,6-tetrahydropyridine), has been suggested as a potential etiologic factor for the development of Parkinson's disease (PD). Aging is an accepted risk factor for idiopathic Parkinson's disease. The aim of this study was to test the hypothesis that paraquat could induce PD-like nigrostriatal dopaminergic degeneration in aging C57BL/6 mice.Methods Senile male C57BL/6 mice were intraperitoneally injected with either saline or PQ at 2-day intervals for a total of 10 doses. Locomotor activity and performance on the pole test were measured 7 days after the last injection and animals were sacrificed one day later. Level of dopamine (DA) and its metabolites levels in the striatum were measured by high-performance liquid chromatography with an electrochemical detector (HPLC-ECD), and numbers of tyrosine hydroxylase (TH) positive neurons were estimated using immunohistochemistry.Results Locomotor activities were significantly decreased and the behavioral performance on the pole test were significantly impaired in the PQ treated group. Level of DA and its metabolites levels in the striatum were declined by 8 days after the last injection. Immunohistochemical analyses showed that PQ was associated with a reduction in numbers of tyrosine hydroxylase positive neurons.Conclusions Long-term repeated exposes to PQ can selectively impair the nigrostriatal dopaminergic system of senile mice, suggesting that PQ could play an important role in the pathogenesis of Parkinson's disease (PD). Our results also validate a novel model of PD induced by exposure to a toxic environmental agent。

Abstract：Background RNA interference (RNAi) is a powerful tool to silence gene expression post-transcriptionally. Our previous study has demonstrated that small interfering RNAs (siRNAs) have sufficiently inhibited hepatitis B virus (HBV) replication and expression in vitro. In this study we observed the RNAi-mediated inhibitory effects on HBV replication in mice models and accessed the specificity of these effects.Methods A mutant RNAi vector (pSI-C mut) with two base pairs different from the original target gene sequence at the RNAi vector (pSI-C) was constructed according to the method described in this study. A mouse model of acute hepatitis B virus infection was established by injecting naked plasmid pHBV1.3 via the tail vein with acute circulatory overload. pSI-C, pSI-C mut and the irrelevant RNAi control plasmid for green fluorescent protein (GFP) gene, pSIGFP were respectively delivered with pHBV1.3 by tail vein injection method. Six days post injection, enzyme-linked immunosorbent assay (ELISA) assay was used to measure the concentration of HBV surface antigen (HBsAg) in mouse serum, immunohistochemical straining method was used to visualize the expressin of HBV core protein (HBcAg) in liver tissues, and the transcriptional level of HBV C mRNA in liver tissues was detectedd by reverse transcriptase PCR (RT-PCR) analysis.Results Injection of pSI-C exerted magnificent and specific inhibitory effects on the replication and expression of HBV in the murine model. After 6-day post-injection (p.i.), the OD values were shown to be 5.07±1.07 in infecting group and 0.62±0.59 in pSI-C group. The concentration of HBsAg in pSI-C group was significantly lower than that in infecting group (P<0.01). Liver intracellular synthesis of viral core protein was sharply reduced to 0.9%±0.1%, compared with 5.4%±1.2% of positive hepatocytes in infecting group (P<0.01), and the transcriptional level of HBV C mRNA was greatly reduced by 84.7%. However, the irrelevant RNAi control plasmid (pSIGFP), and the pSI-C mut did not show the same robust inhibitory effects as pSI-C. Conclusion pSI-C exert efficient and specific inhibitory effects on HBV replication and expression in mice models。

Abstract：Background Bmi-1 gene determines the proliferative capacity of normal and leukemia stem cells. Expression of Bmi-1 has been found in all types of myeloid leukemia cells in both humans and mice. This study aimed at assessing the effect of antisense Bmi-1 expression on K562 cells proliferation and p16 protein (p16) expression.Results K562 cells transfected with antisense Bmi-1 plasmid grew significantly slower than that of controls (the parental K562 and cells transfected with empty plasmid). The colony forming ability of antisense Bmi-1 plasmid transfected cells decreased significantly (P<0.01) compared with controls. The p16 expression of cells transfected with antisense Bmi-1 was upgraded more apparently than that of controls.Conclusion The antisense Bmi-1 gene can inhibit the growth of K562 cell and upgrade expression of p16 in K562 cells。

Abstract：Background Morbidity and mortality of advanced human immunodeficiency virus infection (HIV) have declined in Western industrialized countries since the availability of highly active antiretroviral therapy (HAART). It is unclear if this has also happened in Hong Kong.Methods We studied a retrospective cohort of patients with advanced HIV disease in Hong Kong, China. First, the mortality of advanced HIV disease per year was calculated for the decade 1993 to 2002, both annually and according to patient observation before and after 1997. Second, the event rates were estimated for the clinical end points of acquired immune deficiency syndrome (AIDS) and death. Univariate and multivariate analyses were then performed to identify associated factors. Results The crude mortality of advanced HIV disease declined from 10.8-30.4 per 100 patients during 1993-1996, to 0.8-6.9 per 100 patients during 1997-2002. A rate ratio of 4.04 (95% CI, 2.52-6.47) was evident for those observed in 1993-1996, compared to those in 1997-2002. In a multivariate analysis where calendar period was adjusted, use of highly active antiretroviral therapy was associated with rate ratios of 0.13 (95% CI, 0.05-0.33) for death after AIDS, 0.08 (95% CI, 0.04-0.19) for AIDS after a CD4 cell count <200/μl, and 0.21 (95% CI, 0.07-0.67) for death after CD4 cell count <200/μl. In the same analysis, calendar period ceased to be a significant factor after adjustment for use of HAART.Conclusions The mortality and morbidity of advanced human immunodeficiency virus disease have declined in Hong Kong. This improved prognosis was attributable to the use of highly active antiretroviral therapy。

Abstract：Background Epigallocatechin-3-gallate (EGCG) has been demonstrated to have anti-neoplastic activity, but the effective concentration of EGCG and its possible mechanisms are uncertain. The study on the killing effects of EGCG on different digestive tract cancer cell lines can find target sites of its anti-neoplastic effect and provide a theoretical basis for its clinical application in the treatment of cancers. Methods Methyl thiazolyl tetrazolium (MTT) analysis was made to detect the differential sensitivities of eight digestive tract cancer cell lines to EGCG. The effect of EGCG on cell cycle distribution of sensitive cancer cell line was measured by flow cytometry. By polymerase chain reaction (PCR)-enzyme linked immunosorbent assay (ELISA) protocol, the influence of EGCG on telomerase activity of sensitive cancer cell line was also investigated. RT-PCR method was employed to detect the influence of EGCG on the expressions of hTERT, c-myc, p53 and mad1 genes in sensitive cancer cell line. Results EGCG exhibited dose-dependent killing effects on all eight disgestive tract cancer cell lines. The 50% inhibitory concentration (IC50) of SW1116, MKN45, BGC823, SGC7901, AGS, MKN28, HGC27 and LoVo cells were 51.7 μmol/L, 55.9 μmol/L, 68.5 μmol/L, 79.1 μmol/L, 83.8 μmol/L, 119.8 μmol/L, 183.2 μmol/L and 194.6 μmol/L, respectively. There were no apparent changes in cell cycle distribution of sensitive cancer cell line MKN45 48 hours after incubating with three different concentrations of EGCG compared with the controls. It was found that EGCG could suppress the telomerase activity of MKN45 cells, and the effects were dose- and time-dependent. After EGCG administration, the expression of hTERT and c-myc genes in MKN45 cells was decreased, that of the mad1 gene increased, and that of the p53 gene unchanged. Conclusions EGCG has dose-dependent killing effects on different digestive tract cancer cell lines. Administration of EGCG has no obvious effect on cell cycle distribution of sensitive cancer cell line MKN45. The anti-neoplastic activity of EGCG might be due to the inhibition of telomerase activity by means of its influence on hTERT and the up-stream regulation genes。

Abstract：Background Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) is often difficult to distinguish from other small round cell tumors. The EWS-Ets gene fusions that result from chromosomal translocations in this tumor provide potential molecular diagnostic markers. To apply these molecular markers to commonly available archival materials, we evaluated the feasibility of detecting EWS-Ets including EWS-Fli1 and EWS-ERG fusion transcripts in paraffin-embedded tissues and its diagnostic value for detecting ES/pPNET.Methods Thirteen paraffin-embedded samples of ES/pPNETs were retrieved from archives. Thirteen cases of other tumors with small round cell features (including rhabdomyosarcoma, neuroblastoma, lymphoma, small cell carcinoma, and desmoplastic small round cell tumor) were used as negative controls. Β-actin and β2-microglobulin were used as internal controls. A nested reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay was performed to detect the EWS-Fli1 and EWS-ERG fusion transcripts.Results β-actin and β2-microglobulin were detected in 10/13 and 13/13 ES/pPNETs, respectively. EWS-Fli1 fusion transcripts were detected in 11 of 13 (85%) ES/pPNETs. Three chimeric transcripts, all EWS-Fli1, were detected in ES/pPNET samples. Among 11 EWS-Fli1-positive cases, 7 cases had a typeⅠfusion transcript involving fusion of EWS exon 7 with Fli1 exon 6, 2 cases had a typeⅡfusion transcript involving EWS exon 7 with Fli1 exon 5, and 2 cases expressed fusion transcripts involving EWS exon 7 and Fli1 exon 8. Type Ⅰ EWS-Fli1 fusion predominated over other types. Fusion types could not be distinguished in the remaining 2 cases. Thirteen negative controls did not show detectable chimeric messages. There was a significant relationship between EWS-Fli1 fusion transcripts and CD99 expression. Conclusions Molecular detection of EWS-Fli1 fusion transcripts in formalin-fixed paraffin-embedded material by nested RT-PCR is feasible and is useful for the diagnosis and differential diagnosis of ES/pPNETs。

A traditional Chinese medicinal capsule capable of curing HIV/AIDS has been put under clinical test with the approval of the State Food and Drug Administration。

Beijing will host the Second International Conference on Birth Defects and Disabilities in the Developing World from September 11 to 14, with estimated 1,200 participants from dozens of countries, an official with the organizing committee said here Thursday。

A guide for clinicians in developing countries to the clinical diagnosis of diseease and to making proper use of clinical diagnostic services。

The World Health Organization (WHO) collects and summarizes a wide range of quantitative data from a variety of health domains through country offices, regional offices and headquarter departments。

Investing in children's health is essential to ensure human and economic development. Healthy children have the best chances for healthy, productive lives。

Hepatitis C virus (HCV) infection is a global health problem. HCV is one of the leading causes for acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma。

Anesthetic induction and maintenance with propofol are associated with the decreased blood pressure that is partly due to their ability to inhibit vascular tone。

In recent years, the indications of cardiac pacing have extended continuously with the rapid development of pacing technique. Pacemaker treatment has not only limited in arrhythmias of bradycardia and the number of pacemaker treatment has increased year by year.

β-lactam antibacterial agents are the most commonly used antibiotics in clinic. The production of β-lactamases is the important mechanism for resistance to β-lactam antibiotics in Gram-negative bacteria. As a result of the generous use of β-lactam antibiotics, mutations of β-lactamases gene in bacteria are frequently developed to oppose against attack from antibiotics, novel β-lactamases were found one after another, among them SHV-28, CTX-M-11 and CTX-M-22 β-lactamases were first found by Chinese researchers。

Penicillinosis Marneffei (PSM) is a rare fungal disease caused by systemic infection of Penicillium Marneffei (PM)。

Severe lithium intoxication requires intensive and prolonged hemodialysis as a definitive therapeutic measure. Such an aggressive stand is often needed to prevent the post-dialytic rebound in plasma lithium levels as a result of the drug's relatively slow equilibration across cellular membranes。

Small cell undifferentiated carcinoma is a special type of tumor which is usually found in the lungs. However, it is very rare in extra pulmonary tissues, especially in epididymis. One case of small cell undifferentiated carcinoma in the right epididymis, with partial differentiation to adenocarcinoma and neuroendocrine carcinoma is reported as follows。

Interrupted aortic arch (IAA) is a rare congenital cardiovascular disease with major intracardiac defects and always with multisystem non-cardiac malformations. It occurs in 1: 10,000 births, and about 1% of the patients with congenital heart defects。